Heat 1 tbsp olive oil in a large nonstick pan over medium heat. Cook onion until softened, about 5 minutes. Add tomato paste and sugar and cook for a minute or so. Stir in tomatoes, 1/4 tsp salt and some fresh pepper and cook for about 3 minutes.
While onion is cooking, pour boiling broth over couscous in a large bowl. Cover and let sit for 10 minutes. Or, if using quinoa cook according to directions on package. Fluff couscous/quinoa then add in tomato sauce and stir well.
Wipe out pan, then heat butter and remaining tablespoon oil over medium heat. Spoon couscous/quinoa into the pan and pat it down gently. Cover, reduce heat to low and cook for 10 minutes. Check, looking for a light brown color around edges. Continue cooking as needed until the bottom and edges are nice and crispy, perhaps ten minutes more..
Place a large plate on top of the pan and quickly invert, flipping out the couscous onto the plate all at once. Enjoy!